why if god is real didnt he expressed himself at the very beginning of human history???

Question

we can trace the origins of christian religion but there were other human beings who existed before the christian idea was borned.
just bear in mind that in the time when Aztec or Maian culture existed christian mythology was not (created?, revealed?).

god left evidences but then he decided to send his son..were the "evidences" not enough??? he thought people needed more "evidences"???

christian culture created a thousand years before the aztecs???? tell me what books do you read because i dont want them in my library

Answer 1

God did leave evidences from the beginning through nature, Natural law,conscience, among other evidences.
Actually, Christian tradition and history had been well developed a thousand years before the Aztecs.

Answer 2

In the beginning of Srimad-Bhägavatam it is established, the Supreme Absolute Truth, the Personality of Godhead, instructed Brahmä(the first created being) in the Vedic knowledge through his heart. Therefore the evidence that Vedic knowledge is free from the defects of mistakes, illusions, cheating and imperfection is that it is spoken by the Supreme Personality of Godhead, and has thus been followed from time immemorial, beginning from Brahmä. The Vedic religion or the principles of the Vedas have been followed by the highly cultured population of India since time immemorial; no one can trace out the history of Vedic religion. Therefore it is sanätana,(eternal). "Eternal" refers to that which has no end and no beginning. The Vedic religion is therefore called eternal because no one can trace back when it began. The Christian religion has a history of two thousand years, and the Muhammadan religion also has a history, but if one were to trace back Vedic religion, he would not find its historical beginning. Therefore it is called eternal religion.
In the Bhagavad gita God claims that He comes, but He does not manifest to everyone. He does not reveal to the nondevotees and the common man.